1. Field of the Invention
The present invention relates to a discharge lamp and a luminaire.
2. Description of the Prior Art
Currently, colors reproduced by a variety of light sources are evaluated quantitatively based on the color rendering index, which has been an established method for quantitative evaluation of colors. The color rendering index evaluates quantitatively how faithfully light of interest reproduces colors, compared with a reference light. Recently, however, more attention has been paid to how desirably colors are reproduced, apart from the faithful reproduction. It has become increasingly important to illuminate colors in our living space such as colors of human skin, food, plants, interior decorations and clothes desirably.
At the present, discharge lamps for general illumination having a relatively high correlated color temperature ranging from about 5000 K to about 7000 K are commonly used for main illumination in houses and stores. However, it is said that lamps with a low color temperature from about 2800 to 4500 K are more suitable to create a relaxed atmosphere in the illuminated space than lamps with a high color temperature. For this reason, a light source with a low color temperature is gaining its popularity gradually year by year in the field of illumination in houses and stores.
Furthermore, a lamp with a high color temperature is more dazzling than a lamp with a low color temperature when the light source is viewed directly. Moreover, an incandescent lamp for downlight tends to be used together with a lamp for main illumination as a recent approach for illumination in houses and stores. When a lamp with a high color temperature is used for main illumination and an incandescent lamp is used additionally, the difference in color between the lamp with a high color temperature and the incandescent lamp causes a sense of incongruity.
As described above, although lamps with a low color temperature are thought to be suitable to create a relaxed atmosphere, lamps in a conventional low color temperature range of about 3700 K or less are believed to pose a problem as to how colors look under the lamps. For example, such a lamp allows an object illuminated such as a new tatami mat to look yellowish like an old mat, or the skin of a Japanese person to look unnatural, even though the lamp has a high color rendering index so that it can reproduce colors faithfully and emits three lights of blue, green and red as main emission. Thus, the color of the object illuminated is not reproduced desirably. Furthermore, there is another problem in that a white object such as a paper or a white shirt does not look white, namely, the lamp cannot provide high perception of white. It is also said that a lamp in a conventional low temperature range cannot provide sufficient color identification because natural colors are not reproduced, and it is more difficult to distinguish similar colors under such a lamp.
Therefore, with the foregoing in mind, it is the object of the present invention to provide a discharge lamp and a luminaire primarily emitting combined lights in blue, green and red spectral regions that allows improved reproduction of natural colors of various colored objects, is not overly dazzling, and barely causes a sense of incongruity when used with an incandescent lamp.
In order to solve the above-described problems, a first discharge lamp of the present invention radiates visible light including the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the combined light lies within a region common to the following regions: a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.056, a minor axis of 0.024, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.078, a minor axis of 0.014, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.235, 0.335) as its center, a major axis of 0.060, a minor axis of 0.030, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.225, 0.330) as its center, a major axis of 0.060, a minor axis of 0.018, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; and a region on a side of color temperature lower than an isotemperature line of a correlated color temperature of 3500 K.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that provides excellent color discrimination (identification) and is not overly dazzling.
The visible light radiated by this discharge lamp includes radiation of atoms or molecules exited by radiation or discharge from a phosphor.
A second discharge lamp of the present invention radiates visible light including the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the combined light lies within a region bounded by lines connecting four color points (u, v)=(0.235, 0.342), (0.252, 0.345), (0.248, 0.338), and (0.239, 0.334) in the CIE 1960 UCS diagram.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that allows an illuminated white object to be perceived as white (i.e., provides excellent perception of white) and is not overly dazzling.
A third discharge lamp of the present invention radiates visible light including the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the combined light lies within a region common to the following regions: a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.056, a minor axis of 0.024, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.078, a minor axis of 0.014, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.235, 0.335) as its center, a major axis of 0.060, a minor axis of 0.030, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.225, 0.330) as its center, a major axis of 0.060, a minor axis of 0.018, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; and a region bounded by lines connecting four color points: (u, v)=(0.235, 0.342), (0.252, 0.345), (0.248, 0.338), and (0.239, 0.334) in the CIE 1960 UCS diagram.
This embodiment achieves a discharge lamp that has both of the advantages of the first and second discharge lamps.
In the first, second and third discharge lamps, the color point of the combined light preferably lies within a region on a side of color temperature lower than an isotemperature line of a correlated color temperature of 3400 K in the CIE 1960 UCS diagram.
This embodiment provides an advantage in that when the discharge lamp is used with an incandescent lamp, a sense of incongruity is barely caused by the difference in colors of lights emitted from the light sources, in addition to the advantages provided by the first, second or third discharge lamp.
In the first, second and third discharge lamps, the color point of the combined light preferably lies within a circle having a center thereof at a color point (u, v)=(0.2457, 0.3403) and a radius of 0.003 in the CIE 1960 UCS diagram.
This embodiment ensures the advantages of providing excellent discrimination and perception of white, low levels of glare, and low levels of a sense of incongruity when the discharge lamp is used with an incandescent lamp.
A fourth discharge lamp having the characteristics of the first, second, or third discharge lamp is a fluorescent lamp. The fluorescent lamp includes a fluorescent layer including three phosphors having emission peaks in 400 to 490 nm, 500 to 550 nm, and 600 to 670 nm wavelength ranges as main components.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that provides excellent color discrimination and perception of white, and is not overly dazzling.
In the fourth discharge lamp, the fluorescent layer preferably includes the following three phosphors as main components: at least one bivalent europium activated blue phosphor having an emission peak in a 400 to 490 nm wavelength range; at least one phosphor selected from the group consisting of bivalent manganese activated, trivalent terbium activated, trivalent terbium and trivalent cerium activated, and bivalent manganese and trivalent terbium activated green phosphors having an emission peak in a 500 to 550 nm wavelength range; and at least one phosphor selected from the group consisting of trivalent europium activated, bivalent manganese activated, and tetravalent manganese activated red phosphors having an emission peak in a 600 to 670 nm wavelength range.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that provides excellent color discrimination or perception of white, and is not overly dazzling.
A fifth discharge lamp having the characteristics of the first, second, or third discharge lamp is a fluorescent lamp. The fluorescent lamp includes a fluorescent layer including four phosphors having emission peaks in 400 to 490 nm, 500 to 535 nm, 540 to 550 nm, and 600 to 670 nm wavelength ranges as main components.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that provides excellent color discrimination or perception of white, and is not overly dazzling.
In the fifth discharge lamp, the fluorescent layer preferably includes the following four phosphors as main components: at least one bivalent europium activated blue phosphor having an emission peak in a 400 to 490 nm wavelength range; at least one phosphor selected from the group consisting of bivalent manganese activated, and bivalent manganese and bivalent europium activated green phosphors having an emission peak in a 500 to 535 nm wavelength range; at least one phosphor selected from the group consisting of trivalent terbium activated, trivalent terbium and trivalent cerium activated, and bivalent manganese and trivalent terbium activated green phosphors having an emission peak in a 540 to 550 nm wavelength range; and at least one phosphor selected from the group consisting of trivalent europium activated, bivalent manganese activated, and tetravalent manganese activated red phosphors having an emission peak in a 600 to 670 nm wavelength range.
This embodiment achieves a discharge lamp with a low color temperature primarily radiating combined lights in blue, green and red spectral regions that provides excellent color discrimination or perception of white and is not overly dazzling.
A first luminaire includes at least one selected from the group consisting of a transmitting plate and a reflecting plate for radiating illumination light including the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the illumination light lies within a region common to the following regions: a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.056, a minor axis of 0.024, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.078, a minor axis of 0.014, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.235, 0.335) as its center, a major axis of 0.060, a minor axis of 0.030, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.225, 0.330) as its center, a major axis of 0.060, a minor axis of 0.018, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; and a region on a side of color temperature lower than an isotemperature line of a correlated color temperature of 3500 K.
In this embodiment, the illumination light that has transmitted the transmitting plate or reflected from the reflecting plate primarily consists of lights in blue, green and red spectral regions and has a low color temperature, and the luminaire provides excellent color discrimination (identification) and is not overly dazzling.
A second luminaire includes at least one selected from the group consisting of a transmitting plate and a reflecting plate for radiating illumination light including the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the illumination light lies within a region bounded by lines connecting four color points (u, v)=(0.235, 0.342), (0.252, 0.345), (0.248, 0.338), and (0.239, 0.334) in the CIE 1960 UCS diagram.
In this embodiment, the illumination light that has transmitted the transmitting plate or reflected from the reflecting plate primarily consists of lights in blue, green and red spectral regions and has a low color temperature, and the luminaire provides excellent perception of white and is not overly dazzling.
A third luminaire includes at least one selected from the group consisting of a transmitting plate and a reflecting plate for radiating illumination light comprising the following lights combined: light having an emission peak in 400 to 490 nm wavelength range in a blue spectral region; light having an emission peak in a 500 to 550 nm wavelength range in a green spectral region; and light having with an emission peak in 600 to 670 nm wavelength range in a red spectral region. The color point of the illumination light lies within a region common to the following regions: a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.056, a minor axis of 0.024, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.224, 0.330) as its center, a major axis of 0.078, a minor axis of 0.014, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.235, 0.335) as its center, a major axis of 0.060, a minor axis of 0.030, and an angle from the u axis of 30 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.225, 0.330) as its center, a major axis of 0.060, a minor axis of 0.018, and an angle from the u axis of 20 degrees in the CIE 1960 UCS diagram; and a region bounded by lines connecting four color points: (u, v)=(0.235, 0.342), (0.252, 0.345), (0.248, 0.338), and (0.239, 0.334) in the CIE 1960 UCS diagram.
This embodiment achieves a luminaire that has both of the advantages of the first and second luminaires.
In the first, second and third luminaires, the color point of the illumination light preferably lies within a region on a side of color temperature lower than an isotemperature line of a correlated color temperature of 3400 K in the CIE 1960 UCS diagram.
This embodiment provides an advantage in that the illumination light that has transmitted the transmitting plate or reflected from the reflecting plate is not overly dazzling, and a sense of incongruity is barely caused by the difference in colors of lights emitted from the light sources when the luminaire is used with an incandescent lamp, in addition to the advantage of excellent color discrimination or perception of white.
In the first, second and third luminaire, the color point of the illumination light lies within a circle having a center thereof at a color point (u, v)=(0.2457, 0.3403) and a radius of 0.003 in the CIE 1960 UCS diagram.
This embodiment achieves a luminaire radiating illumination light that is ensured to have the advantages of providing excellent discrimination and perception of white, low levels of glare and low levels of sense of incongruity when the luminaire is used with an incandescent lamp.